By default when someone shares any image from your site he shares this image with URL of page where this image is displayed.
For example, you have page with URL https://your-site.com/cool-page/ and several images on it. Someone shares one of this images. Than if any person see this shared image in his timeline of any social network and click on it he will be redirected to https://your-site.com/cool-page/, not to URL of individual image that was shared.
That is how plugin works and this is good way to increase your social network impact. Of course, there are ways to change this default behavior and customize shared URL.
But it is not very cool if user clicks on image in social network and just redirected to some page. He need to scroll down and look for image that he clicks on. Special for this plugin has option called Auto-scroll that, as you can understand from its name, auto-scrolls users to image on page where he was redirected.
Auto-scroll option
So when this option turned on user will automatically scrolled to image that was shared. Vary convenient, isn't it?